The present invention relates to an apparatus for detecting a radiation temperature or a human behavior, and in particular to an apparatus for detecting a temperature distribution or human behavior in a home living room, with the use of a thermal image.
Conventionally, a quantum type infrared sensor and a thermal type infrared sensor have been used in order to detect a temperature in a non-contact manner. The quantum type infrared sensor is highly sensitive so as to be highly responsive, but requires cooling (down to about -200 deg. C.), and accordingly, it is not suitable for the people's livelihood. Meanwhile, the thermal type infrared sensor is relatively less sensitive so as to be less responsive, but does not require cooling, and accordingly, it has been commercially available.
Among various thermal type infrared sensors, a pyroelectric type infrared sensor has been frequently used.
Such a pyroelectric type infrared sensor has a differential variation output characteristic, that is, it delivers an output only when the input temperature varies. This pyroelectric type infrared sensor normally incorporates a compound eye type lens and a shutter adapted to be periodically opened and closed, and accordingly, it detects a time variation input such that the radiation temperature of a human body periodically bursts. Accordingly, the pyroelectric type infrared sensor delivers its output in synchronization with the above-mentioned time variation input.
Further, it has been proposed that these pyroelectric infrared sensors are arrayed two-dimensionally in order to provide a means for obtaining a two-dimensional image.
However, the two-dimensional array of the pyroelectric infrared sensors causes a system arrangement to be complicated.